SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81e3fd372dc1e78f7827a26bd02a8625b0e80e9229305537b40040e4e67f554a' 
  AND token = '6qUffPvKDpqzueBYDrYCw2BZhxZww/MdO5Ef34+F4tw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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