SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67961fde19893d77b88082462b32f78c73a26c30188fcbfc4c9f65a35fe80bd4' 
  AND token = 'ZYfld3V4GuTPApil+halmgBRuyf4zPCQw8kz382bNSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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