SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c28763f6d4470039120c5852d191becd7be3d155e650606611ba3652d4bfe5ab' 
  AND token = 'OcKb91+xe2c5802Xq6hvPKKyufhVd1CRCwY5DGrDphY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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