SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3bcce4a0b93114a21a1cab6878e31cfe3d3bc4d983a6fc666336b51890033078' 
  AND token = 'J4nNaqDYtWq9VOYew1SG6R0wel4ITny0EhVh6DauBqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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