SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '30b12030e89b61637c3a10d4577833d6f516e4d9caf2947714650bf9f16270b9' 
  AND token = 'rl7PT6LjJRxmFONr9qQ51uI7GzxlDyiCT0tqjiGmJnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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