SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b47881dcf5ab41605e9a6671ef49e929633b6628891bdb5f084cc8c6005a9539' 
  AND token = 'KVhIncsNdDUfWpz/7JV3nvERCPTdJ8uhq7Es7qJKGrc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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