SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ee55d1e429dc400ee744eeac8ced5c25b5ccfa11c7644b51d9003c51edbb571d' 
  AND token = 'Ou+SrUPdnnwbnyoyx1Bb8pmdvxhXQK6opWGn+v+/65c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}