SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e1623d933219d83c8119cec40cbc2ff50287e78049d7e947621e569352737846' 
  AND token = '43cK2goY79QKpZnxKi63qaIuPkLt6U+/blYSiOQO6ms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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