SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd8effe4f2db53861c1e6936ff596a09d638df9e8efe786c9b50b9a1bf590778' 
  AND token = 'OleaXy/dMo/4RqXUUog2xXHzkL8WVae60DFMfgxwCsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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