SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39039d5fa74c6e86e01cd351306a1809c8693a96c6d522de4611b586fddbbd28' 
  AND token = 'td16mImTqyaBkXNoGvzVhOIohXz38iDJ1tWzrjhUZnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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