SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f35a08a0ac01bcee4bfb424b86da7259adb8b17d15911c30ea0c883c2c34982' 
  AND token = '0KHEdumB1jtFdt6yQerErOavvnPncsjKiTkcz8EP6Dc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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