SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21bd3ae9565d948566119ee9f7fa34c430b2b32798f92627eced632eebf3e41a' 
  AND token = 'hyD5LiJh1+kF/yqhwsarRzheL+wYJr+mJZ/BTETrR8M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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