SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '08dac6f2d1c638448edc134e37bb3893d8ee3f42d459c2f16e99c9e80a5daaa3' 
  AND token = 'nqb7NYzpUOLhpUMpdw1PBk+t0NKGMIA2hVml5d1DYm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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