SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f648a40d09d20cccd00ca173bd395f6dc6fb9cbbf03264d6eff8f358bf8da49' 
  AND token = 'qXriUVjb8KLMyITEZEpK0t9dtIaxdGtSI3VLrtgqghw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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