SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a06657599e63dfdfa4a8b76c396371e0b2517366bd4b2b76c27315bda323b0a' 
  AND token = '5KYlZMSqX+VPj0qNnJx3T4hP8jPG8HiPC3UUdYNqzk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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