SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20917eb7414becbdb9d6098f963a97d82af419e126d960302c5795f04093bc05' 
  AND token = '5clodBmOGijaiWxfkHgFPQtfNDcF5YCYWGIZf+mW+iE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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