SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4174c6bf47f4922a96f95df9bd77b655b2a81c44f287f53c42a9330d392da838' 
  AND token = 'm4MQ7375JWUplR2+zzTiB9J2dazG33pRMIEz5ygaj8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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