SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77ef2ba3c0cbe2584c73c25b3e14cade6acc1b49f3abd9426569c2caa2bf0180' 
  AND token = 'PKOoXyfMVX8XViYMAdrvEnmGDk+/ABoJBSnF2/MZhms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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