Demora na consulta sql

Select 
   c.NFNUMNOTA, 
   c.NFTOTAL_NOTA, 
   c.CLICNPJ, 
   c.NFTRANSPORT,
   TRFONE, 
   c.NFDATAPED,
   c.NFEMISSAO,
   TRNOME,
   c.NFPESOBRUTO,
   c.NFPREVISAO_ENTREGA,
   c.NFCLICOD,
   c.CLIRAZAO,
   CIDNOME,
   CIDUF,
   TEM_ADIANTAMENTO,
   ESTA_DEVENDO,
   COBRA_RESOLVIDO,
   COLETA_RESOLVIDO,
   CHEQDEV,
   CREDITO,
   DATASAIDA,
   DATAENTREGA,
   ENTREGOU,
   RECEBEDOR,
   PREV_SAIDA,
   VOLUMES,
   c.NFNUMPED,
   LINK,
   LOGIN,
   SENHA, 
   n.nfordemcompra, 
   vendnome, 
   n.nfStatus,
   case 
      when (Select 
                      First 1 cr.crcontrole 
                  from cobranca cr 
                  Where cr.crclicod = c.nfclicod) is null
      Then ' ' 
       else 'X' 
   end Cobra,
   case 
      when (Select 
                     First 1 co.ocorrencia 
                  from Coleta co 
                  Where co.nota = c.nfnumnota) is null
      Then ' ' 
      else 'X' 
   end InfColeta,
   case 
      when (Select 
                     First 1 ico.ocorrencia 
                   from inf_cobranca ico 
                   Where ico.nota = c.nfnumnota) is null
      Then ' ' 
      else 'X' 
   end InfCobra, 
   nfRedespacho, 
   usunome
from Dados_Coleta c, nfsaida n, vendedor v, usuario u, cliente c1
where n.nfnumnota = c.nfnumnota
   and v.vendcod = n.nfvendcod
   and u.Usulogin = n.nfusuario
   and c1.clicnpj = c.clicnpj