SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '727ae94527fbbe911292fa4b7abecda29acd3027be5bd53030334f0f4d1c2af2' 
  AND token = 'f4zrJy8Z6UHwUb77sLkYNpCAOO/M3KAYmgEC87M2T1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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