SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6fb36b387694539d5face6cef52f6c827d283bace92310072361f55a7b2a560' 
  AND token = 't5ZJL8SBqhHAXvVqTGpzIiionjQBHOjIx/OvJyz/cy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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