SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10a40e473f64e7935903147ce1788988ef201f377896df318e6befb6c83a0246' 
  AND token = 'blv3sizvLlcNlCi5GcY6FXL6jGQCVQiYjg6/kw5A0zY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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