SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd04bb231731600c307ac963e7048e20fa1aec67121c71306dd7e907f8bcdad88' 
  AND token = 'KgnxcMySnzfNq+qXA5yJfaqsfuyNadCH+V9xhpsQHgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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