SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38193b9656d5420d6fb73685389aa6b0e1d8effae62faf6601caf1c43c0e500f' 
  AND token = 'i/f4LTXk/sFuXcs81guPjQxZYXgS2KJ+k+7N/FrGIz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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