SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f11f969bee76f807d9f520aa93efbec7ee4b7e617412bf63a52aee07be9eaec6' 
  AND token = '/3K+aFeOPXGFS8Bf/F/BjJQeVIWNqQ65fxehN0DlOwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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