SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd38fb673a869812eabfb82f71c1d4e4fd2b70b09cce86b994af8d8194f3524a7' 
  AND token = 'W/7t6DgJ0/2jVGmxpIVxGfpAGaW9DBfnURM5JXhEUTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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