SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '447f4a02f0f3f06b9f6cac539c202e39d5a4e3adca720b0a9981595c5a7304ad' 
  AND token = 'sjgm6OzTDivpH5Q3Jk9uVgzIPXoqCBRIXHtqjPKFI/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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