SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d5f5975c44a429baecdfeaaabce8d373d67273fa0e3aae339692b86f9c7359e' 
  AND token = 'BBOTM9akN0SjpdNGCMal+5ehKgMOj0j0OAGYonTyN5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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