SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff79d552d1ea98a18b2c83056dd6688abd918c84583ad63000ef50cfdc6c35d1' 
  AND token = 'WGSkShYToqhnNlSmb/OUrEnJL1XNHOpMl2HBqnQd5OA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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