SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3013917e481390638e2a2505533ca900a18358c71b69e585ab01363bece58ba' 
  AND token = 'd7c+tq/GoLzIZjucVWmMikgkuXTzRncJSuO2+q1F/J0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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