SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23b7000ddd45048ef1de1e4edd1351c28f29607efe32e35aef4ed977b7faada4' 
  AND token = 'UCwXBX19r7IdcSU+M1XMlAllYA6r1wOphUp9JFxGijk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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