SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f27e7b5f2afc46ac751fd060686363244287aba13e333103b586b4de16d3193a' 
  AND token = 'dey3RzlHwjyOMCErlD4VUTVKwMgP2uM/h/Gi5JsjZkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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