SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d349fd19e6ffdf458b546020b6106205d94576ec4617813d3bc3b6ec847176d' 
  AND token = 'RC/wWlKJFsK3kofiikgdo6VckD6n4nytYWCp4XgxPIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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