SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab412b39579eed0f810d7f9fe0dc9cb6c3c732c4a652c890d264455783b494e7' 
  AND token = '4VZRko3aJcUQJCTw/4wE+vVwG4cI5PahzBVGms8nVLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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