SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b9be8062465ae282b5352aa5017157847537d35dff3587ac2b98fa7cbe676f5' 
  AND token = '3FSBC/rrh/B1gXGQybJLG843tHKDG30ZkbXBvGWhYYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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