SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c843427aa280a2406d8de7ec6ffec838dc23b6701caba1989fe085a31bda649' 
  AND token = 'MBbkK8ErRfvp+aCn/Q9wlMsgl/oF1oBV4mQyhG4Zn+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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