SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd684eae26600fd3a73f07b91099280703657819453b820a7e01354792d2b05c9' 
  AND token = 'cUioe3ZCa5EayM04tWqzrh0R5DauWhLIt4sNkWXSDgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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