SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8ebe5daa5cabe1059fcd9cea4a4bbf85d8046f41d9efaf07be95984671372a9' 
  AND token = 'o9jS5iec6rpPaavquyhj1IqtcZEJWjGIo8kkX+AVSoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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