SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc54121c9cb072be2b393a95cf1a6f83bcdec2f177fe44f636fc2289f2a6a831' 
  AND token = '5ikgXuGn5AvNHUTKijruuhfUV08iPG3s0IvyXaBJzqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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