SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78ea60e1c47fe02657e9bcce7aee647a954e3d5bbe14e897018c03118f195964' 
  AND token = '4cYiyNx23JDMkT2NIoXHcfEkWAiPwhZsNNgWzfzSssc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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