SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18066cedecfcebc601d6383799d334864c20560ee6fb8e8f845dcb8c4716f71d' 
  AND token = '1S8tF99ucFVtNWqPZiQ+OQhfbY9R2PZayVLVGFW/ppQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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