SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8e8c443640371748308999f47deb873112c624b3ef2bf605112f50d889d005d' 
  AND token = 'NLh4qmWHpKIlD7HQy8SMdz/VYgpja06+/UvBE+UhJFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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