SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3f3ab31a18ee23e3757a2bdc1992e47baf0653795e31979a8b9269ad7fea5b1' 
  AND token = 'hH7e1U5WhXob0H8ysoIOhjOp+43/KzE2Q+frgcrGtd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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