SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca0ace4ae012d3a51a6baad4e36ae74970caa37457f6305b3b9028233731f227' 
  AND token = 'yGQ1sbTUsBHLcNmR2VuiqJv+D47kMztsDSrlDilds3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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