SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c5c456a9cca0bb482d7be8797a9f860da772b04f9c43b5bcde1b9e435490bc8' 
  AND token = 'srWRBHXFE++sY/rCxz75WpJUy2iL+QqG5FmhNPXYTDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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