SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '762b1525d34030698e75828d53752395e90fcd53173662fd5f5645e0c83dda10' 
  AND token = 'alwZZxYyuftaiXCDkijYCrpsAYCiKRVpba/qmxpizPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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