SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea0c183bf270d303717998ca9747874fffef9daaea3832d59f589da572d028a7' 
  AND token = '57Pv+QnoZHpX58sMRsjuxP7MDyAv3KLYMwPMYunHzAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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