SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2bffebb6cd5cbafa09821bce5e2fb54df2d4c48f35d209e223338618a4f055a1' 
  AND token = '3tnG6VGHaJS4JjRGYzAV8IcluMrLl8FxiA/6pRZiBNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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