SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92b5047e524db9bd7822b18dbad63474ffdafa51c524ef872790f40ef616e18f' 
  AND token = '0Puj65zY+yQWNkLuRvZJMYNszp2RmwS2H9gePILfHn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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