SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e40ed88fc5883fd848b012f12b2e023fee6cb70519b76baff8b66f551b85de4' 
  AND token = 'hXHoSPWiLpX/q3RElnarUYx6TxI+bUkGeJMb1obz0yE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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