SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '19596e2d433710c75b0ff49f9bd453fcdce6398b524be3d9b21534ed2a253a34' 
  AND token = '1oqJOUNi5FNDcZ8QdDwcbWpp+56IGo9ZksGJbEKyk4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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