SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3491c64e633fa73201134d165975f7bb43fb6637672a01367e506b93fe4614ad' 
  AND token = 'x9PnnltEKls9etL27/sFuryjRta63SZBsoSmF5im8iA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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