SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62b6d206b7b8153391fb092186494596dee816cbe55fa2afa0ed5c6d73c48b6e' 
  AND token = 'pumSIqdYx7az57CbHTs/GlgDlzJAF9/oNOCBWvT+yoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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