SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6a882df8a2f62ed762eef445546f8ef37dba12b3da2d5350cb440b1e7849761' 
  AND token = 'G62dOwy8YqI8qFP+ZRTQtBDAqJBqOe07NrkYc9ISAKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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