SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56a3009c2cb92247a8a67fea4f561014f67d1429c8c842dbd88b27a4f07896ec' 
  AND token = 'uJ6PLz7Epsusjjvjyh5NHOs+pIq+j3R3bR1xX6R/PHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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