SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '584bfc88519a601e809382ec55603f8dca223113378a1abb4e4be7430b5b7d99' 
  AND token = 'pnjd/nQu5xlmTBYIkqJtUGjaNWhM744XkpSHsNDNGwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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