SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e8edfa5b430f0fbd3a23db11b97575670072f958c7b4f719c7e13b9a43ece87' 
  AND token = '3cv0D29tt0pVY70NxmMuDqIUWZFomIKqKKSbtDk8eXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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