SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd98da96f32a521d14e39ae0914eb1de6cebb1673c9551dd037c0bda1639d27b' 
  AND token = 'qnkVIdfhCkl3ADh7ZPkU2SceMGvFaRCwpkUwVqGdVrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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