SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c600c301bd6cd60ad70f74edcb26e3921b026bbdbe376fe21f36a3c1ff15dea' 
  AND token = 'zHykujjW5JAk6pyc1wdp8p9S/ba11WQsh1FbshUZe2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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