SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '275e6e12b79493126d2390898a611f1673652309d9f79f34d34ed1bf1e142db7' 
  AND token = 'CSqoHR7FOU5ds4/FywOUSCXHCYBAipjzWIs3GTZvoMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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