SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '38723df0212dbb0a9f6926b715182ff5b18086cc57e0658e306d94b38fa4c348' 
  AND token = '+TZcgIn7/aGHiCmhxfsyhjhWn/n4qFhj/DSSWp8BoEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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