SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad690104ae573a0a0719d26daa47db3f650366e862f5cd246734bc01b1b6044f' 
  AND token = 'DCBSstSOKMRDErxG4mUbGCp5ymJRarOJ1NrbHh0PmJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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