SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dc8dc923148d63d2d88d6561b0575893beb65d4a84836666a6f454b0963537b' 
  AND token = 'vTgqdkbmJTT8/4JNA75jWEsyucyu4sIP/2NLzaCBf5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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