SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc34be06279a2d3885ae0ca60955bfb3b6d3affa4cece507bf07ad0d08351645' 
  AND token = 'l6Zd2gXTqvVR5hN+w/cuHOT9CSGmAqgfhJQZBrPdPAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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