SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5fcb68995afc95346cec588ad98fbbd8c7a24f5b79dd3dafc1935e077e87044' 
  AND token = 'L6bGkcCaceiSUDfBMBYmuxvECFC7F6VoB0336pcSljs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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