SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24df364004fa1aaa85d5d8bba756cce82511a03e726895b8fe8651e2ad475b57' 
  AND token = 'dZ4jo5cHn0/au1EXTWFmS3om8beAZg607qs7+ul+ajc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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