SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dc8d605b51fca44a48635579aceb7ebe85ffff4cbfa414deed3848c76251e2a' 
  AND token = 'oOQivvq/nXFSDvyxTyCzW4NLvE2RkbwQWmWe9Sf+TJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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