SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f689d02aa28deeb64b4aa6868c7e223150e102ff3876f72090f56236469e9abe' 
  AND token = '6Y4baaCImmF6/TjhQvd/zETvJ+MhxG7Yif+uHKB54lU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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