SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94c87da9be01e78d2204550bd617850eb974fb3fe19ba3eecc8c8e174d31b42e' 
  AND token = 'Y2ceZvVzCMoGOXhqZ3qrvKnEWtQP6DJAS/96VXbCMpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}