SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed9515f85c9fb3991c37723432844628dddaf09fdb2806fc7504a063008b3701' 
  AND token = 'Kq4u/09zBpIsU5tRIi0x09pJ/7+QBBdMFzGOXB6z8fk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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