SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c15561963d92f8e25e71d57a10f3be595b7d54c0f5d7352ecb4fa286a4e615de' 
  AND token = '01RGJkEjwjkDB6UHlmAqzZNBXgdvBjsOskv6dSgaLdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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