SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04b3a837fec8c2a244081283f5d5deff1977416dbe3988db2402896078c54f59' 
  AND token = 'ZGNwE2oKnKowblwzhWYRJHsL+1IFqeWPzuYjHbE9sM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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