SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a04458b518a3db6e8243559cb50218086b60d3cb5a742a1df9a3d9242350c466' 
  AND token = 'AYavKYGVN03cXkwxPEo2hHz/uXYKN5dcd5iMbalbwIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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