SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '571bd157eca350a845ccea4e8ef743901a3504b3dc98506e4f3824b8138e766b' 
  AND token = 'HdGYSgGb0hmplYpqTRf6YFLecfIs55fMEiV4R4SyvsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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