SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fe7f3d8420c31d98bbb254f37c8ffb44e55a7a034a5e95305317d497ed80c60' 
  AND token = 'w3GHpmQzjZxw+/Y8YYdt+7krXBvH+MMV/AejsXCWDio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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