SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55ba6b8f5422f96e63502642f75c4428034bbae370d792c40bc0d4dfb03d52ea' 
  AND token = 'xaoKFWBShKT6nmczdFdMfISHfxHvikNBymeQqCfi6Ac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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