SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '365486707f5698232a284149e242c876f32a99175eb4cd1e5abd0ede14c27b2a' 
  AND token = 'Iwc5JvZhBnwozxSXmwoZNqXlCM8oP7InCQsnYCvY54M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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