SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3ed2d8e09202dffe4245ca0162736e22b9449ff6a33cb4c89ac623363a51445' 
  AND token = 'JbiqodHLZmu88z8oqwzOQs7k1UqTBFECygoUoU5cRio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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