SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '928ef2aeccf087ed1508c5be4f404288db2cf0de08cbd47bd501ab231409366c' 
  AND token = 'WGYrs0JkEUB59eMcxZfhmwa8mJM/IIv5gK0/XK7TBNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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