SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c476e85bf8d97801566d1a7528fb7cbf43056bd6da43526fbf91629c5aa13fa4' 
  AND token = '843bAhWb1wz9em8Fwz9PI1H+/C1ZJZanxkJFXQMFoqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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