SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aecf0fd9f46ed752eaa5fdd7bf936afef313b02e3d09a5816280b73acb0da431' 
  AND token = '5UN6I4LQwEWqjzd5e7t2IGaBB0wUaRyYqIYqIyfH4dE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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