SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46a43f88953976ce5b99656fa0600526597f199d9b7ea7e52bd39b279f224a94' 
  AND token = 'CjJSVH+dM2I3PEHh+n3jMvIMZGWwebWnMpYgzj94+RE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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