SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd6bb4f58d238416adcbc6832c97c48d5b0684d6fc75bd71cf6364c21b8f2080' 
  AND token = 'cK6KCIqd44j8TxX4EjFcxOvLiwgkzCSQczKlZmQm/Vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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