SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '791eca1a9f8ed7d8419312cafee59fb63cc22a952fe62b8671e0c36881254603' 
  AND token = 'FkuH/92mgPHjp4NMvGyftXNSchvYqChTfhjZHlwXhHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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