SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c64037c3309691d9a1e8bd70e5efaf923a3baa59f644a3924c528af03eafdbbb' 
  AND token = '5FdNJkgcndKWHrsLMocSmNnJ9jTruQCRhDSo5egu6WI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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