SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58415a5ee1d6835e784db612080a96412795d7d3bb3941cdbf8eb65a97f0b8b3' 
  AND token = '2FxnYA3LavtWqwphJmD/jtC9I8eM4C1XTUJ/evUXZg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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