SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0930a7a5d65166eef9cc4da2afeadcd59fb8d792f25aa253b3197bae57e9e816' 
  AND token = 'pig9zqo3+BrqABBqRIQFZ4/PtxWAjakat4y/EGxmzwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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