SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '399838fb0104d66215c6f87ebf0503da6c7905df72fe25e563ab1572c52ce542' 
  AND token = 'M7wSwUpX/uXdFTyppkqDkvHMP7DqJ0sH+J9WuUgkx+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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