SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2bbdf03c02d9a87582ea8fc234c21fcc99ae75932da5d8c42dd409ed5a7b156' 
  AND token = 'ETGuOtx5YdBigeakmeJQhI98wgGPN2hzmU/OnXSNoF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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