SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2d27adc5766f4559193b9f65dfef00c7590f302465c6983a7761a4aaca2cb27' 
  AND token = 'SsvCK2UXhylRMkh4qu3Hck3b3lrG4j1ro1xAcXk2ho8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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