SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ad10405264cee766825144a15fad9ab495521f34cc5383aa5be79af559d504e' 
  AND token = 'gKOaLgWl4TrBSgCLNUEcF4Cilg8lD382MLplgGWiI3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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