SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '192fca3b94fd8b731da5b193e39cab1cabbab84972f87a09c815fffde5184b30' 
  AND token = 'YnWzr1/CV4wd5V8NyH5rvkzXN4uCga72SUiR1NbwWQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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