SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f3f96d7fe5375f564724497d4fd1101e671b89603ff0568b8461ed141ef35606' 
  AND token = '6yHlBrIybRZqMqP/haCcdWxxTumBwpuO1Nihe5/6wUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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