SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '660d4b34fb5e139572f249ed50b203f436d0344618845f3f0aa3a42f059adf6c' 
  AND token = 'rhI/uWhuBB74bTkPCXXdEfQmiXu8Ur/cm+jbDVjvFkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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