SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f26911add45da562d15ac0b9b3ad637663ff471415fc5aa037e797da42ba448' 
  AND token = 'mBkz6LeEyJsRhOzW/QQbYQZl4qU385hB2YKUMkKgX0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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