SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ac5a7a842118485b301b48d7391e97dbbe9fe4fc0a42d727cc79354299a540f' 
  AND token = 'IFZgADeVTnAR2hIRUaaFGAp64hAwvdEnP3Yju9BzkXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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