SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6b65eabe579b236ae4f515d283503936815d8fb1ad890f976944debab482a3f4' 
  AND token = 'IN62fPn3CjZ6IFHOpgnztlWsvyKpxZMb7OMoZjca+jo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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