SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f3f7763d541f7ef0d11c4bc3869a5dbe22196198c261193e8c0e43dbe281867' 
  AND token = 'wGsFClvPeLzbYG+qjUIVEZT0ru6mVjajkcdmqii3V1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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