SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88df35e15f09019b3a13bc1ca43dd8873cad92807f977b39878cdd2ea985439b' 
  AND token = 'wnKOdYmXc5lHY59zIKKvC533ZB5rrWOZlfGrmtZ6nTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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