SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '28202692e0ae19c40853d4a7bc5fcf9a7190ba65a566fdc528cdb5a4c7a92be9' 
  AND token = '3V4e5+bK1IQyNv3BAzIKUUAVPsvTy8c1UpVKh2a2CZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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