SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb3d289c02e8ccddaed455bfa3448c4e4bdb2bf4021f377f2795e96f22844e7d' 
  AND token = '0uwCtPEAJOdqi4rtllEZtfi2C3UOvo5bVeZ4M9NdUYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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