SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a38dbef2f69eea78848e34a6bd3576a77e65b7ef2634a0b1bc761d03591a3d9a' 
  AND token = 'qQRHj1TvapkM8jE01y5Q7TYIXfm8/frddzm89t0rUOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}