SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c081d61d971f6c1678b311b8599711ea3f2d9f628ba1520777bc56fb2bde90f' 
  AND token = 'BscyPnPxlqXgRkUXUV+t5+FlNYBVAhBZZ/LCrL0yA+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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