SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '680e80a365beebc402078f8a87890e1b97ca95263de907e987012515fa3e3ec0' 
  AND token = 'qS6OVQ23YTmDBIPMdyqmAxF4oN2jnOJpOuNGkpC4GPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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