SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd67f7f78d07882ce894aa53d08c6a409e3e6aa2c12484672385ea927c232aefc' 
  AND token = 'JHu+3SpAvVTpoltqu12a91zOd0zaF6Yq1MeiewezcGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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