SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffb9993ad437b803d0f4a939dd495ae07785fd18803cfcf1609d29cbd732943f' 
  AND token = 'qfU3Xkwp66Fbj5nAKQSxObzFZHpJQKv4njz32qOKpUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}