SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe3b05bae2e6357594813e3366abc1ddb904c73e9de26d002437ec159d260b38' 
  AND token = 'ttvWLcwriQZ6jetzIUXcOmG9cqT1qZWygKY78U8q9XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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