SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '20c7790fdc5641a10bf425c2582446b2dc969641cba66b05d70ff29a16e9744e' 
  AND token = '/xOPrdVbSJkqu3yT+4cZ8KG35lRje1LPje7j4Y75UBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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