SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46f8281d4c47cdce28cf71ed537bccd37ee7ae266fee8a7b30a95c605fa92889' 
  AND token = 'KgzLULvjobi0BuDgPwUFPmzGY/AFVsWSKEvzl5aEFl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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