SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66d83e732a6dae07db39b628bce6df59c53096f0b0a90b1fdc45acee8ffb8a5b' 
  AND token = 'xLFJysqhsHqNeWhxDLC+fxUFAqpT2KreA0TLXY2Jzbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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