SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f4b6deb7dbb28f26292d7fb767b301ceb9d60dd0a5f93a3396c30a4c5752a0a' 
  AND token = 'ECEDguGhC3KT8D13CZUDbq+PPRzFo4XJWL+TYKHEAAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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