SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1892dee569b27bc524c744a994f93a54a95bbeab1439cf301aafd46cd9cfd7b2' 
  AND token = 'MAVSVEF9CPnwOPwRDmkLVDlCBL6t+8hHYK0KxHgzjPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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