SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c4b572f51987e490830448e237efbf994fd1061f85e459ad89a8baf90c97bb8' 
  AND token = '77wB3niQuAa3dMHYXiMtSOODgrNxlFnstTCGUn5UlxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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