SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '636538d6616644a1b4f95788ea9ea9b09e5bcac0f3f70ec10ac0dc202218fd91' 
  AND token = 'qRfoD5ssSIUl/DLZgLW9TsuM01FZa4JLmInPgoKJlEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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