SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '579c2c34681d5c6310d761270a7101148d8d42baab85ca785dfb19953c3b4ca9' 
  AND token = '3v6MwTAGXwJx1nBlnT084aQQSDtOgA8oBCC1+6YnfF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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