SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8f29565113d9b5c2e74591e4cd049803f8d22b1b109dae23e05349a8f628a872' 
  AND token = 'sDiElxPv8DeDglsIjXQXhFOz17y0FXipHi62dpB08yU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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