SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '878c7b17cd65e9413e94dcf233e28d3094ca9885b1b7c2673f9ed35901199853' 
  AND token = 'ZJHRPrv9vXYJJVoUwuh4lU0SdLPQLP3FGsKike69ZI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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