SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c672efba88df39470e9be38dfb1154f0054b5734a81ee19664898afbd4b25602' 
  AND token = 'ZMnL2aV0XBN4IeC0ObEPZAFq+vgsKuSDKQ/+vHvBrZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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