SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5f383f4a44af5a02213fffe088dede2750c8e36b7e81edc01766304bc9be24b' 
  AND token = 'zRMMEbdkBfk/Y+VhKvv6aJfqOwUbRRlTjhQFNKqWVao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}