SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f1f46c18bd58092f7d50529b6d9d38072477332a1ce651f6de08e4d12a4a60c' 
  AND token = 'q8P32DpnZGNFofUCZnnDHHFuSkDmbUKAXkIWRH3Hce0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}