SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c31b41465f1646d612bb78f91aafa34ba8517124a65b825ac5296a6f44e96fee' 
  AND token = 'krY0dGqoILUL/bU/oTqjRTCE7GREBLNfcjTyPrGmVkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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