SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c5f697989fa9b4af4b785160f0d9b3cebe491493af3ead52507033369429c2e' 
  AND token = '2WiDW7Bq+eownFVC7E+TC6AiuZUtkzgv8D0o7xhWJ48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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