SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd38f16c568cf4a7da84a59801ce2208df49f889b513072d50166ab63f643810a' 
  AND token = 'gfg+i2vHQNUewKZtB/vKhIhURj/ys8WaOo5+2K2wE40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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