SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55f36526e16cb4230e09b992bf74e090fe78c7934fcc876d8796148753287cb8' 
  AND token = 'DyZDO52gG1dfSPszfAk/xC1WvDpCZ3wOlY/I3LchWvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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