SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ada2c12d8c393ebd1f9661dc2ab23b742d87e30cf87d0bbb132304a267cb547' 
  AND token = 'KUbRHjNnArGIZlIvRHK2NVgOvDNZCswyKQH/7MjibyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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