SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8b67c3e7e7e3b56094638048f05a47e05fb9e2187a06ce647b0cdb950118a55' 
  AND token = 'DKJUXeaavKerceZS5+kWtmnbq67RCzSwYM0NihbPGz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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