SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4356a6dcb9b80d00d224560107d523dc149f34290145644e149cec26a96dc9d' 
  AND token = 'tfdZ/uso7zirjJ0ihd7L+q/nxTa4uxnJt5rAismONQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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