SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0011d97e5a63deff40c7578d1589e375ef01cea64944c4e600b84aa1b313d557' 
  AND token = 'hhBgbuEF0isiLET9yEoqx45/MP3YMVoqLoySckwq4dM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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