SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5128627200af4dbd674f643950229a5066f120d76c5c09026a1aac76e8423f1b' 
  AND token = 'qYxzIEKwIMCDokEa1HstXwPfLbM4DIApJ+q/SUa1dak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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