SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f066b9f370ee4a0f400ad4fba2ad012efb1d63ac3bb44579132504f8baa1b9c' 
  AND token = 'segzrqxzCEdwzZfLvxAbmDZkttHzNz1E47MukCOlWQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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