SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fda0ecda0e16db692ab0593869a6c4705383b9c4f519b0701dd63bf3960b0dd' 
  AND token = 'nxvW3wKP7RJiVZ/GJQoNPRkuiYUEk5rCMHVOgT6oXCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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