SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fa9b1924cc31deadbbc9ade8f3ca0b822353aaa5c5ddc33ae94cee212c57ce9' 
  AND token = 'DAvT0wlWBAo+mYUkiDMUF7KWmdPPV4pa85QCT1vQke4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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