SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a876deb6073066699f37e54c20588d57f1aae31adc5e24aae0b0510587b047aa' 
  AND token = 'cESLaj6eJUI9skY4bj0POCFCNuEewY4Kqa8gwziQk5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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