SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4863890abc63e0a8d78662ff52d36e15ad96a089136c3f1b4f466a85fbdcdcfd' 
  AND token = 'xv067VwxUWraq9fMLYKyrLfPCWwh//Zo/i8WxtO33LE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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