SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f70b2592964004dad5f82c58467ff9f342adb1de96fe2d0644e7030ff16c424' 
  AND token = 'ncQJnRoWUYGuXYcbgOt69Sw7W3EMAhChqwptvlpxBPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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