SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e58570c37db2439ec0676ca1ae07348c44d842bf344eb56b5af8a9ff2aebb1db' 
  AND token = '4UdWWT1GW1sHVM+L9uyzXZjGg6Y1PQTv16OPaP+RzuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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