SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70b3e8adbd8f4fd0332455951769db10edfd05324ad480d6b9d90a60fc30ab7c' 
  AND token = 'wmvue/ylARwj5siEF5CIOKoFw4aVYkMIT+CdBukYHsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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