SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3641389303dd2c8351987230a3eeb14f57ef4ea71409b17f45c236a4df4a804' 
  AND token = '2JRIXtmf45/Kvy0FrfORivsvt8+gjJLpbbeF8kkNMH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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