SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96cf66f75f8e5ab8bdd98a8608c5fe8a0b849805c37177dcd4dd3373dbb2d339' 
  AND token = 'xBYODARprHDgXZBt7EMbiUiZzbQpekl4ZBLS5dmTLz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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