SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '191dc3df519f9d808be31f004dd62eac184d30165e0ae01b080cb136f673c1cb' 
  AND token = 'EnzdPY4eL5M8mIecCM6aSYUZ0I+GepZlxeAETMUze9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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