SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '485b2934daff435948d62e2227dfebcbbb0964123bd50b6b47cbafb7f302e951' 
  AND token = 'szQtwHtisrlWR4O9EYJrfkEAO/FW742roVcjkzM/JII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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