SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6edc6826ba6e1017db6679331e33c3a106ab1d82bab5573efd029d4218797bc8' 
  AND token = '3OZLfUbMKwJzjgSmSokJC8R6MUmr3dBgCYOg/oGxt+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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