SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8604f8daf062215d6d3e517d77968958b74bf3cc4ebc8a7d2773c38f60651f44' 
  AND token = '9Pv/u1NOfx3dlTEWB6F/3K5xJhTznH0TCH/NTLZxfs4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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