SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b749c19aea8973237c29ce0ec79696ed1f9e2e66bf0bb9a852661272a5ea536' 
  AND token = 'XlAOgpfe8Jg19AFwHP2KCQa9BLRYQ4U5ugXfehuTaJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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