SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c1786232ef8c1885f7a0e99dc02a11e750967e6dbe691d90e1c370d6c52630a' 
  AND token = '+8BxmcIknrBgq1qNzJsbqLTuXHIsxP/68uKSp+mh3w8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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