SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56049dbf824ffe03e283aa23e3ee7d4096163d343764301249b56f53634ad936' 
  AND token = 'jUgp44cweGhybXex41hpwnOGjYuYemIUsQW0wrViqSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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