SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6abaa8cde72144b783bff4e364e3e30b6f65dbd45c09c3649d1909d876cc6392' 
  AND token = 'YTXWUSyf2mM8em5tZRAEyEwXrvCUg+RyxqZlkhriLdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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