SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd484ca3f28752d7b7a67178668a483d5373a0fbefc3b066d91156901ebecfcdc' 
  AND token = '/pdNZb50EQMBRLcjCx5RxiFbKCHjpgyVzmoYFmKi3Po=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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