SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9554bff21f095485b3334b74910af541df01d0766f0326c82102ebeae4168c06' 
  AND token = 'j076pRCkD9T0hswdrEHJejolJBuGtSoyEVzHG1FhHBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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