SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b0f8f499558860a603cd52a04e92490191d72dda68778dcff18abffa281dc58' 
  AND token = 'vv+gtIQ9vtLRshnXK4xbnF0QYH+qNkW+PpZ8aVhupOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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