SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8e0173c96cd2cb1ec41f393de682588a9538c1dc01ae284a5c7402147bb8476' 
  AND token = 'vlC9c1Ik3aMUg8OZE2vD1yRf7qeHFkSh924WEaBPljM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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