SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ea78a81c242b4a4eae02f999ca6c0924807da3c06e92ec45be7a9a17e67acc5' 
  AND token = 'UsDbXaCPfZpZPCyjTsluBONAk/+UwErtJiQTyD0mBYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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