SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ae77b448623c2c347dd0a5b3d8ebd95dfe50f94d0bdd0e5da29436fdb247529' 
  AND token = 'RGYSaU/UxuQIJd9fDQ+5+sNCtellhCfxxZ3F4jbTr5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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