SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '750a805ecd9037656d87e47a50e654e8d903f3e87a8881a075516a4bb6c6bedd' 
  AND token = 'vwebOEhmu+pRvnpQ68ha15pu9wGs1YQlGwpEz5cjdiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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