SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d246e3aaeb66ec2b24819a53f840808b9c0fd264a1517b643b5b3ce29d563f9' 
  AND token = 'kOnpCUA9S2nKH4QELJddTDkJpAULPyCWn5VlEh8D8/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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