SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4933090af1975108292da62aa866a592db3349d9758bdf5aa99ba1d8001d2a32' 
  AND token = 'lfu5kxD2li2150UZPLbI4oNxoNCK7ytp8zpcbHr4vUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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