SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '372afaaf115ef2612f61958d98d3af1a101761c30487e9d08ca767df8be6ef25' 
  AND token = 'kShX/pQjioh813f7dYgZaEwE4PhSZOjXvOLh+NVWTb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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