SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a4b7a7a7a03488b9566566b285863432bac7a660baccf8d88eefc6d15467ea1' 
  AND token = 'yewn5qxNqWoYOmSIBV1JwWqhGU34ImnUpwjcFhi/n84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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