SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51ff9e81bd179206f67f684e0d6221c7896499159a33b0bd3ca8c9f134328551' 
  AND token = 'ieZjJBCjZY1T4RD6VTXSwHYEqOo9BjU6Jg/7IsTqrkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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