SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2954b0eb5bd746c113697616003faff487521211867d60ba092968caaea219b8' 
  AND token = 'ZXPE8Z5byiD+amp/6l6rBSqtXjUKn4qpicPN1YU5IuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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