SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5ce412572febea81568d566fd0dd0ccc556f121f5df69e4aad22598d15428358' 
  AND token = 'PIB2XWJryfqHLLqKcEZbO+olVVUk20dgFpT10K14vyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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