SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bd453f7f56578732936d7e9a758995c4017534c85c50a4532a5f704d4b47c84' 
  AND token = 'prZSAzsXYF/WDVUEod4XC/q8Qh858sEBR86IbeVzNBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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