SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6047bdf01efa667fd08160b323b1e7e1fa1d0f93033a861fdd35f2a03de7a49f' 
  AND token = 'EIVc+34UDBQsT4RCFTbCq7xUILbk9ky3ya89YSkDpsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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