SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '12ea8f4075a09188285ae4337aab091abed21315e184e0bb81d3c2e84e671427' 
  AND token = '9fDnbpQibTPoWdxV1K4UPhypB52PhVctHlOock1U9XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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