SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c69c579e59f19d82a70e42efda7788890e3c2cf7a1bbd6a8791593ae30dc596' 
  AND token = 'BSs0YgFoKCb3RNh8JD6ylLqEMnqTp7IbG6X+V/2PjZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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