SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84d9217736ccfbc82ab800c1dce4f6a111826941fb7a8476af1a4321a0af3a49' 
  AND token = '0vqCV/s08nxKIHwS0Z9ilE83EoYTuX7RQUnzNy3JM8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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