SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b46915da18762b72f7e1fae0b8c1d13ad2146ddbd4cbc3312f3f0726bf64978' 
  AND token = 'rQJjS3bzAa5RrAaT6qElR1fqzjYZp/e4V8/GKTVv3tQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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