SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9ce55dad9b6c99523e94dbc0031f8c857a271043b15ae35afb685e59443777b' 
  AND token = 'ylT7/hnjexrtJjd8VyJrH+OifkfyArIMojn9miX/arU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}