SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1bf4cf1958e70d8f2c21ac27a136c4f9bfe990493b877ef2144a5f3cbdda8aa' 
  AND token = 'isp7IQSZLvZl2/KSC3xpDDJTmuhvFVWUlC1XKZ5d29U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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