SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f200fde55681205ae924f02b0f1b7701bcdcd88c33836f71b3943e88a9083ca' 
  AND token = 'bTfKtRhxEdw0GMkGX5sCRbYtyRRLoSgcmaD8vKI5oxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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