SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c553f4b7eae014dfdc64c26037ff7149579032a663553b62df38864f1489b7f7' 
  AND token = 'ghJYDJufqUXMhvcsqLarKlmoAAQ6frEIFMBMSLIFVq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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