SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f0ed8471538619406f2cf6a82f8ce47905368cb3299c7f600454f2027fa1bec' 
  AND token = 'TylswsBqRxkrCN4FbAHMTmJNDJgqvvufgxqqxhgX8Ao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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