SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b9cb80ff8b146fc08d822a4ad411094d5379d4e4a06c289b0fd3a70587251ee' 
  AND token = 'qzo1/th3XuAf/BAClqdheLsNnWREZx4AGNSuzriZWDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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