SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41107959aa84e0c73ea7315545402dd971afbabf4a753fb69500389ba6820f58' 
  AND token = 'AMHcyK7zqJYdjhAsyGA51cId94cvUMRkAvoeK/4CYsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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