SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c04a430737c5a1b205c6281168f53b6fbfc23c549ad4d1f17646d182c92b3e64' 
  AND token = '687ThYEbH1Qt0984WuSr0Vu+GoDCfubc/0gnWBSyqxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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