SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f16a0eca7bf8512050fdf99d11f057ceb8f9314648d5b23a8c62ffa5288861b7' 
  AND token = '/fcreWug0lf02gyM7WUMBcCTIyyjn/VIHtqyYiwwY+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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