SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cabb145b80ba58fa8b321317769680ec6608d41bd89061e9f1505a3265395e3f' 
  AND token = 'RuRRq9cG/yo1VrTsaplzGkCfTHkENW7KwwfzGmvZktQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}